Application handpiece with lamp of novel shape

ABSTRACT

An essentially u-shaped discharge lamp ( 13 ) comprises a gaz fill and a pair of electrodes ( 15 ) at its ends. The lamp ( 13 ) way be comprised in a handpiece ( 1 ) for treating a surface by means of electromagnetic radiation.

TECHNICAL FIELD

[0001] The present invention relates to an application handpiece and alamp for said handpiece, designed for use in equipment for medical andcosmetic treatment, and also for all applications in which a flash lampsource with the smallest possible lateral dimension has to be used inthe proximity of the surface to be treated.

[0002] The lamp is a source of photons which, with suitable intensityand time-based delivery control laws, can be used for action on thehuman body, for example depilation, by causing irreversible damage tothe follicle and hair bulb, or other treatments which require highdensities of light energy on the treated surface.

BACKGROUND OF THE INVENTION

[0003] At the present time, techniques of removing excess hair are nolonger applicable solely to women with problems of hirsutism orhypertrichosis, but are commonly practiced on patients of both sexes,who are not necessarily suffering from specific diseases, but mayrequire treatment for purely cosmetic purposes. The procedures commonlyused for this purpose can be classified according to the duration of theresults. According to this classification, there are short-term systems(razors, tweezers, cold and hot waxing, creams, gels and electricaldepilators), and long-term systems which, after a certain number ofsessions, can even yield permanent results. Some examples of this secondgroup of systems are electrocoagulation needles, radio frequency scalpelneedles, non-coherent light and lasers. Among the long-term treatmentmethods, the greatest success has been obtained with the use of systemsbased on the theory of selective photothermolysis, which cause damage tothe hair bulb by means of the electromagnetic energy absorbed by themelanin present in the hair or by the hemoglobin of the follicle bloodvessels.

[0004] Non-coherent light and laser depilation systems are moreeffective when they strike the hair in the growth phase (“anagen”). Thegrowth of hair is not continuous, but cyclical: a rest period called“telogen” follows each growth period called “anagen”; the transitionperiod between the two phases is known as “catagen”. The duration of thecycle is different in the different regions, varying from 2-6 years forthe head hair to only 4-8 weeks for the eyebrows. According to currentbiological models, the cells giving rise to the follicle are located inwhat is known as the “bulge area”. These cells form the new hair matrix,thus initiating the growth phase. In the initial part of this phase,when the follicle is shorter, the papilla is closer to the skin surface;subsequently it increases its length, proliferating for a period whichvaries according to the anatomical location. It is in the initial phaseof anagen, or anagen 1, that the “target” structures of the follicle(such as the papilla and the bulge area) with its vascular system arecloser to the hair and to the skin surface; as the papilla and the endpart of the hair become closer, there is a greater probability that the“light” energy absorbed by the melanin of the skin, and that whicharrives directly, will cause irreparable damage to the papilla,permanently blocking its ability to make a hair grow. From what has beenstated above, it is evident why the action of a “photodepilation” systemis more effective in the anagen phase.

[0005] In a non-coherent light depilation system, use is made of adischarge lamp, normally consisting of a cylindrical container ofmaterial which is transparent to the electromagnetic radiation in thevisible band and in the near infrared. Inside the container, at asuitable pressure, there is a pure gas or a mixture of gases, accordingto the characteristics to be obtained for the emitted light spectrum. Atthe ends of the container there are two electrodes, positioned inglass-metal seals so that one end of each electrode faces the internalenvironment, where the desired gaseous atmosphere has been created,while the other end forms an externally accessible current lead for theelectrical power supply. The structure of the discharge lamp istypically rectilinear. When the lamp is excited by suitable levels ofvoltage and current, according to time-based control laws, a dischargeis initiated in the mixture contained in it, generating the emission ofthe radiation. The lamp has to be very close to the skin, or moregenerally close to the surface to be treated, in order to obtain themaximum intensity. To maximize the effectiveness of the treatment, thehandpiece must not mask any part of the surface to be treated withportions, such as the electrodes and current leads, which are not activebecause they do not emit radiation. A good illustration of this point isprovided by the depilatory application. In this case, the irradiation ofthe skin must be carried out in a uniform way, in order to avoid havinguntreated areas or areas in which treatment is repeated, especially inadjacent areas affected by two successive treatments. In other words,the operator must take great care when maneuvering the application unitcontaining the lamp, in order to provide continuity of treatment in theareas adjacent to the area concerned. It is therefore very important forthe operator to have a full view of the portion of skin or other surfaceconcerned on which the radiation is to be made to act, wherever theapplication unit is positioned.

[0006] The conventional structure of the lamps described above does notallow the irradiated portion to be viewed satisfactorily, since theapplication handpiece has two inactive areas, namely the parts occupiedby the electrodes and by the current leads, where there is no dischargeand consequently no emission of radiation.

[0007] To overcome this problem of masking by inactive parts,application handpieces have been developed with conventional lamps, inwhich optical guide structures are placed in the emitting region of thelamp to guide the light towards the surface to be treated, thus enablingthe light source to be moved away from said surface. However, thesehandpieces are of complicated design, and do not fully overcome theaforementioned problems.

OBJECTS AND SUMMARY OF THE INVENTION

[0008] The object of the present invention is to provide a lamp and anapplication handpiece which overcome the aforesaid problems in aneffective way.

[0009] These objects are achieved with a lamp as claimed in claim 1 andwith a handpiece as claimed in claim 5. Further possible advantageouscharacteristics of the handpiece and of the lamp are indicated in thedependent claims.

[0010] Essentially, according to the invention, the structure of thelamp is modified by changing the conventional cylindrical structure witha rectilinear axis to a C- or U-shaped structure, preferably with acentral portion which is still cylindrical with a rectilinear axis, butwith the two terminal portions, in which the electrodes are fitted, bentback, preferably at 90°. There is no reason why the lamp should not havea curved axis in the intermediate area, but the rectilinear form ispreferable because of its greater uniformity of irradiation and thereduction in dimensions which can be obtained.

[0011] In practice, the bending of the terminal portions can be made tostart at the ends of the light-emitting discharge, in other words at theends of the electrodes; alternatively, the bending can start in theportion in which there is still emission of light, but with a sacrificeof only a length of each of the two terminal portions equal to thediameter of the structure itself, so that the discharge starts in thetwo bent terminal portions with the end result of a greater uniformityof emission by the rectilinear area. In this case, the electrodesterminate before the area in which the terminal portions are joined tothe central rectilinear portion.

[0012] With these new types of lamp, it is possible to produce anapplication handpiece which has a contact surface equal or approximatelyequal to the area to be treated. This smaller surface is the onlysurface which has to be applied to the surface to be treated, and allowsthe operator to juxtapose the treated portions accurately because of thefull view of the operating site. The advantages of this solution overthose known up to the present time, which use handpieces withrectilinear lamps, are:

[0013] a reduction in the lateral dimension and consequently theachievement of a better view of the surface to be treated and betterhandling qualities of the handpiece;

[0014] the reduction of the distance between the lamp and the surface tobe treated makes it possibly to shorten the light guide which isnormally provided at the window of the handpiece from which theelectromagnetic radiation is emitted;

[0015] the shortening of the light guide permits a reduction ofabsorption losses in said guide;

[0016] the shortening of the light guide makes it possible to cool thetreated surface effectively by means of the lamp cooling liquid.

[0017] Furthermore, the physical dimensions of the handpiece and itsweight are much smaller, for a given treated area, than those of othersystems based on conventional lamps. Additionally, the light guide,being of limited thickness, remains entirely inside the handpiece. Thisensures that, when the lamp emits light energy, this energy remainsconfined virtually completely in the treated area, thus reducing to aminimum the lateral emission which tends to dazzle the operator, aproblem that typically arises in systems with a light guide whichprojects from the handpiece.

[0018] The handpiece according to the invention comprises a pair ofelectrical connections for the lamp and a housing compartment for saidlamp, said compartment having a window for the output of theelectromagnetic radiation generated by said lamp. Characteristically,the electrical connections are placed side by side and are positioned onthe same side of the housing compartment. The connections are preferablyparallel to each other, but this is not essential. The orientation ofthe connections with respect to each other depends on the shape of thelamp.

[0019] The placing of the connections on the same side of theelectromagnetic radiation output window provides a particularlyadvantageous configuration of the handpiece, enabling the aforementionedadvantages to be obtained. In practice, the electrical connections areplaced—with respect to said housing compartment—in a position oppositesaid window. The position can be such that the lamp lies in a planeorthogonal to the plane of the radiation output window. However, this isnot an essential condition, although it is preferred. This is becausethe lamp can also be positioned in a plane which is inclined withrespect to the window, although the orthogonal position provides anadditional reduction in the overall dimensions of the handpiece.

[0020] The lamp is a discharge lamp and is essentially U-shaped.

[0021] In the preceding and following text, specific reference is madeto depilation, but in fact the lamp and the handpiece according to theinvention have other medical and cosmetic applications (for example, thetreatment of vascular skin lesions such as port wine stain, hemangiomaand telangiectasis), in addition to applications in the industrialfield, for example in processes of drying, polymerization, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will be more clearly understood from thedescription and the attached drawing, which shows a practical,non-limiting example of the invention. In the drawing,

[0023]FIG. 1 shows a partial section through a median plane of thehandpiece according to the invention with the lamp fitted into thehandpiece, and

[0024]FIG. 2 shows a view along to II-II in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

[0025] In FIG. 1, the number 1 indicates in a general way a handpiececonstructed according to the invention. The handpiece 1 has a firstportion 3 forming the handle and a second portion 5 integral with theportion 3 and extending therefrom with a tapered shape terminating in awindow 7 filled with a light guide 9.

[0026] A compartment 11, in which a lamp 13 is housed, is formed in thetapered portion 5 of the handpiece 1. The lamp is U-shaped, with anessentially rectilinear and cylindrical central portion 13C, to whichare joined two terminal portions 13A and 13B, into which the electrodes15 are fitted. These electrodes, on which a seal is made by the glassforming the container that constitutes the lamp, project from thecontainer formed by the portions 13A, 13B and 13C, to provide currentleads 15A for connection to a pair of electrical connections provided inthe upper portion 3 of the handpiece 1. The electrical connections,indicated schematically by 17, into which the current leads 15A arefitted, are parallel to each other, as are the electrodes 15, and areplaced on the same side of the compartment 11 in which the lamp ishoused. However, the parallel arrangement of the connections 17 is notessential. The lamp could also have portions 13A and 13B converging oneach other, in which case the connections would not be parallel.Additionally, in the illustrated example the lamp is shown lying in aplane orthogonal to the plane of the light guide 9. This is the optimalconfiguration, but there is no reason why the plane in which the lamplies should not be inclined with respect to the light guide 9.

[0027] A reflector, indicated schematically by 21, is supported by ablock 23 and is positioned within the lamp housing compartment 11. Thereflector 21, which has a suitable shape (with a parabolic crosssection, for example), reflects the radiation generated by the dischargelamp 13 towards the window filled with the light guide 9.

[0028] The block 23 is carried by a plate 25 fixed laterally to taperedlateral walls 27. The plate 25 and the block 23 can also consist of asingle component. Within the components 27 there are formed ducts 31which open into the compartment 11 in which the lamp is fitted, andwhich are connected at their tops to tubes 33 for the introduction of alamp cooling fluid circulating in a heat dissipation system external tothe handpiece and comprising for example a heat exchanger and/or acooling battery. The portion 5 of the handpiece is completed and sealedwith a cover 29 of plastic or other material, which is carried on thefront of the window with the light guide 9. A seal is formed around thelight guide by means of a gasket 30 between the light guide 9 and thefront edge of the walls 27, onto which the light guide is pressed. Thelight guide is housed completely within the cover 29 which has arectangular housing forming the window for the output of theelectromagnetic radiation generated by the lamp 13. Thus the lightradiation emitted by the lamp does not escape laterally from thehandpiece when the latter is applied to the surface to be treated,except in wholly negligible amounts.

[0029] A fluid, typically water, is made to circulate in the compartment11 by means of the ducts 31, to remove the heat generated by thedischarge lamp 13, and this can also have the function of cooling thetissue or more generally the surface being treated. The components 27and the compartment [lacuna]

[0030] Annular gaskets 35 are placed above the plate 25 to prevent theescape of cooling liquid toward the electrical connections 17.

[0031] The connections 17 are connected to electrical wires, not shown,which pass out of the handpiece in a cord which also contains the tubes33 for the supply of the cooling fluid.

[0032] As clearly shown in FIG. 1, the U-shaped configuration of thelamp 13, with its central rectilinear portion 13C joined to the terminalportions 13A and 13B, makes it possible to produce a handpiece having aspecific shape which is tapered toward the window for the output of theradiation generated by the discharge lamp 13, in such a way that theoperator can have a virtually complete view of the area to be treated,and can thus carry out more precise treatments, without either leavingareas untreated or treating the same area twice.

[0033] The arrangement of the electrodes 15 and the correspondingelectrical connections 17 which are placed side by side, on the sideopposite the window filled with the light guide 9, enables the lightguide to be made with a shorter length, and therefore with reducedthickness. This yields the advantages indicated above.

[0034] It is to be understood that the drawing shows only an exampleprovided solely as a practical demonstration of the invention, thisinvention being variable in its forms and arrangements without departurefrom the scope of the guiding principle of said invention.

1. A discharge lamp comprising a pair of electrodes fitted in acontainer containing a gas, characterized in that said container isessentially U-shaped and has the electrodes at its ends.
 2. The lamp asclaimed in claim 1, characterized in that said gas container has anessentially rectilinear central portion joined at its ends to twoterminal portions, which are also essentially rectilinear, in which saidelectrodes are housed.
 3. The lamp as claimed in claim 2, characterizedin that said terminal portions are orthogonal to the central portion. 4.The lamp as claimed in claim 2 or 3, characterized in that saidelectrodes extend approximately to the positions of the joints betweenthe central portion and the terminal portions of the lamp.
 5. The lampas claimed in claim 2 or 3, characterized in that each of saidelectrodes extends for a distance approximately equal to the transversedimension of the lamp from the area of the joint between the centralportion and the terminal portion of the lamp.
 6. A handpiece fortreating a surface by means of electromagnetic radiation emitted by adischarge lamp, comprising a pair of electrical connections for the lampand a compartment for housing said lamp, said compartment having awindow for the output of the electromagnetic radiation generated by saidlamp, characterized in that said electrical connections are placed sideby side and are positioned on the same side of the housing compartment.7. The handpiece as claimed in claim 6, characterized in that saidelectrical connections are placed, with respect to said housingcompartment, in a position opposite to said window.
 8. The handpiece asclaimed in claim 6 or 7, characterized in that an essentially U-shapeddischarge lamp is housed inside it.
 9. The handpiece as claimed in claim8, characterized in that said discharge lamp comprises a containercontaining a gas and having an essentially rectilinear central portionand two terminal portions which are joined to the ends of the centralportion, and in which the electrodes are housed, said electrodes formingcurrent leads by means of which said lamp is connected to saidelectrical connections.
 10. The handpiece as claimed in one or more ofclaims 6 to 9, characterized in that said window is filled with a lightguide.
 11. The handpiece as claimed in claim 10, characterized in thatsaid compartment for housing the lamp is cooled by means of a coolingfluid.
 12. The handpiece as claimed in one or more of claims 6 to 11,characterized in that it has a grip portion and a portion connectedthereto, which is tapered, terminates with said output window and housessaid lamp.
 13. The handpiece as claimed in claim 11 or 12, characterizedin that it comprises ducts for the circulation of the cooling fluid,these ducts extending parallel to the tapered walls of said portionhousing said lamp.
 14. The handpiece as claimed in one or more of claims6 to 13, characterized in that said electrical connections for the lampare parallel to each other.
 15. The handpiece as claimed in claim 14,characterized in that said connections for the lamp are orthogonal tothe output window.
 16. The handpiece as claimed in one or more of claims6 to 15, characterized in that said lamp lies in a plane orthogonal tosaid window.
 17. The handpiece as claimed in claim 10 at least,characterized in that said light guide is completely housed within asealing cover of the handpiece.
 18. The handpiece as claimed in claims10 and 12 at least, characterized in that said tapered portion isdelimited by a sealing cover provided with said window filled with saidlight guide, the cover pressing the light guide onto an inner walldelimiting said compartment for housing the lamp.
 19. The handpiece asclaimed in claim 18, characterized in that said cover has a housing inwhich the light guide is completely contained.